I'd like to build a 300 blkout AR15


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Gdbyrd
January 25, 2012, 11:48 PM
I'm very interested in this caliber, I'd like to build another AR15, and I've always wanted to own a suppressor.

These three things bring me to this thread.

So I own two ARs now. One is a colt preban that's a safe queen. The other is a lower I built, with a completed upper I stuck on(it's a complete dpms setup). I think this time I'd like to take the full on plunge and build the upper myself too.

I plan on spending like 200$ a month on this project...So I will be buying a few pieces at a time; I am in no hurry.

Just looking for suggestions on what pieces to buy. I think I'm going to go with one of those Armalite stage 2 lower parts kits(for the 2 stage trigger). I don't have a clue what lower/upper I'll get..or what barrels to look into...This will be a plinking/play gun for the most part; I plan to use subsonics exclusively right now.

What can I expect out of the caliber for paper accuracy at ranges? Even if you have to rainbow stuff, I enjoy that sort of stuff a lot.

Thanks guys. I'd like to keep this thread open to keep as a log..even though it'll be slow going.

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Tirod
January 26, 2012, 10:51 AM
If the shorter range ballistics and trajectory are what you want, go for it. All it amounts to is a barrel change. It could be done just swapping the one on the DPMS the first month.

Depending on the source of the barrel, ammo, and optic, accuracy will likely be a spread from run of the mill to OK. It'll take a lot of reloading, shooting, and finesse to get it under .75MOA, but it wasn't ever intended for that anyway. It's a close range suppressed gun with longer range capability for deer or hogs out to 250m. All you do is load different ammo. If rainbow is fun, try 400-500m. You'll get it.

There's a lot of interest and marketing going on right now with it, even tho it's been around since the 80's as a niche suppressor round.

303tom
January 26, 2012, 11:51 AM
If you are going to build a .30 cal. AR why the .300 AAC Blackout (7.6235mm) ?

Expensive & hard to find ammo.

marksman13
January 26, 2012, 12:28 PM
303tom, I can agree about ammo being tough to find in some locales, but we must have a different definition of expensive. Ammo prices for quality 300 BLK ammo are roughly the same as comparable 223 Rem, 243 Win, 308 Win and 30-06. About a dollar per round for hunting grade ammo.

I just ordered a CMMG complete rifle in 300 BLK. The deciding factor between it and a 458 SOCOM was ammo price/availability.

303tom
January 26, 2012, 12:56 PM
303tom, I can agree about ammo being tough to find in some locales, but we must have a different definition of expensive. Ammo prices for quality 300 BLK ammo are roughly the same as comparable 223 Rem, 243 Win, 308 Win and 30-06. About a dollar per round for hunting grade ammo.

I just ordered a CMMG complete rifle in 300 BLK. The deciding factor between it and a 458 SOCOM was ammo price/availability.
Yeh, but I was thinking 7.62x39 at .35 a round. Faster & more punch

marksman13
January 26, 2012, 01:00 PM
It's not significantly more punch but it is significantly cheaper. Just depends on rather you prefer an AK platform or AR I guess.

303tom
January 26, 2012, 01:15 PM
It's not significantly more punch but it is significantly cheaper. Just depends on rather you prefer an AK platform or AR I guess.
No I was talking AR....

http://www.youtube.com/watch?v=9ijCvZmo4NM

Mike1234567
January 26, 2012, 01:21 PM
^^^ I know most folks already know this but... typical 7.62x39 ammo won't benefit much from a sound suppressor because it's supersonic.

OP: From all I've read... yes, 300 Blackout has a rainbow trajectory and... from all I've read, it is very accurate. FWIW, I bought a .458 SOCOM but I "might" buy a 300 blk in the future.

Zane
January 26, 2012, 02:17 PM
I bought a CMMG upper and built a second one. Make sure if you get a carbine length gas system that it is designed to work with subsonics, unsuppressed (CMMG doesn't guarantee that).

I chose a Wilson barrel and it is great fun with subsonics. The rest is up to you. I used a Rock River two stage trigger but on a future build I'll use Geissele.

marksman13
January 26, 2012, 03:16 PM
I know a lot of folks haven't had the best of luck with 7.62x39 in the AR platform. Almost seems un-American to me any way.:D

Well Now
January 26, 2012, 03:38 PM
303tom, I disagree regarding hard to find the ammo. If you are talking about local gun shops and Wally World, I will agree, but there is a ton of Remington UMC and Gunn ammo available online.

OP, you have to decide what you want to spend then google 300 blackout and start searching. There are a lot of companies who have jumped on the bandwagon once AAC completed the testing. Robert Silvers goes as RSilvers on many forums, he was the head man with the 300 BLK, find his posts and read them. he gives a lot of information.

ac6916170
January 26, 2012, 03:52 PM
Take a look at Bison Armory. They just came out with a 6.8 subsonic. Hangs with the 300 blkout subsonic and kicks it's booty supersonic.

Mike1234567
January 26, 2012, 04:37 PM
^^^ What's the bullet weight of that ammo... and what's the rifling twist rate of the 6.8?

Gdbyrd
January 27, 2012, 12:07 AM
What brand of upper/ lower receiver do you guys suggest? I know they're basically all the same. But what do you all like for your builds. Probably going to order an upper receiver next week after pay day.

FrankCastleThePunisher
January 27, 2012, 02:14 AM
Daniel Defense now has the 300 acc blackout rifles and uppers. DD make good AR's.

68wj
January 27, 2012, 11:52 AM
^^^ What's the bullet weight of that ammo... and what's the rifling twist rate of the 6.8?200 grain for the subs with a 1/7 twist barrel. Claims to shoot full power loads too.

LiquidTension
January 27, 2012, 06:38 PM
Take that first month's $200 and start the paperwork for an SBR. It'll take 5-6 months so it should be approved by the time you get the rest of the build ready. 300Blk does nicely out of a 9" barrel.

GI_Jared
January 28, 2012, 11:29 AM
What brand of upper/ lower receiver do you guys suggest? I know they're basically all the same. But what do you all like for your builds. Probably going to order an upper receiver next week after pay day.

The barrel will be the most important part of your build, followed by the bolt, then everything else can just be mil-spec. I personally just finished an upper and I used a Wilson Combat barrel, Palmetto State Armory auto bolt and carrier, and then everything else just had to meet mil-spec quality. Like your thinking I also ordered the upper first and the best place I found to get an upper was Range-Tool. They are a contract manufacturer that has just started selling uppers to the general public. I picked up a stripped M4 upper for $61 and the quality was exactly what I expected, Mil-Spec.

As for the barrel, I seriously suggest a Wilson Combat Barrel. They sell match grade stainless barrels for half of the price of other companies like Noveske.

Wilson Combat Match Grade Barrel, .300 AAC Blackout, SBR Tactical, 11.3", 1-8 Twist, Stainless- $249
http://shopwilsoncombat.com/images/TR-300SBR11-001.jpg

Wilson Combat Match Grade Barrel, .300 AAC Blackout, Tactical Lightweight, 16", 1-8 Twist, Stainless- $249
http://shopwilsoncombat.com/images/300aacblackout-tl-16-001.jpg

helotaxi
January 28, 2012, 12:24 PM
The barrel will be the most important part of your build, followed by the bolt, then everything else can just be mil-spec.The bolt can/should be mil-spec as well. It is the part that most often wears out or breaks. Only the barrel is different in the .300BLK compared to 5.56 and mil-spec.

GI_Jared
January 28, 2012, 12:47 PM
The bolt can/should be mil-spec as well. It is the part that most often wears out or breaks. Only the barrel is different in the .300BLK compared to 5.56 and mil-spec.

Sorry for the confusion, but I wasn't talking about the differences between the 5.56 and 300BLK platforms. I was trying to say that in terms of parts the barrel and the bolt carrier group should be the two parts that make sure are the best quality. The rest can just be random Mil-Spec manufacturers at the lowest price you are able to find.

helotaxi
January 28, 2012, 01:43 PM
Again, if the bolt is mil-spec, it can come from the lowest priced source as well.

Tirod
January 28, 2012, 02:18 PM
Quality does not equal highest price.

Case in point - how many times have you seen common retail on a item, and yet the identical one can be had with a little surfing around for 50% less?

Seiko Dive SKX007 - would you rather pay $249.99 or $129.99? It's the same watch, both imported from the plant in Malaysia, same warranty. Yes I did jump on that.

Milspec M16 full auto bolts aren't made by that many different companies, they all compete for the same business with Colt, and claiming milspec means they better be. Check around, you'll see the same price difference.

I bought a nitrided carrier with bolt from my barrel supplier - all matching at that point, and it still came in cheaper than the "premium" priced ones from the Big Name. Don't let price be a major discriminator in buying, check the features, materials, and construction. The better ones aren't cheap, but no sense blowing money on something that doesn't have their Name lasered on it. Save that for the bling rollmark on the lower.

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